Electron discharge device of the magnetron type



-June 14, 1949. P. L. SPENCER ELECTRON DISCHARGE DEVICE OF THE MAGNETRON TYPE Fiied March 27, 1945 2 sheets-sheet 1 @@x n@ n MM. MQW/ A AFav/ m5 June 14, 1949.

P. L. SPENCER ELECTRON DISCHARGE DEVICE OF THE MAGNETRON TYPE Filed March 27, 1945 2 Sheets-Sheet 2 Patented June 14, 1949 UNIT Erl)y vS'Tii'lfES PATENT UFF I-"ICI-l';v

EI'iEGTRON-DISCHARGEDEVICE 0F MAGNETRON TYPE Percy L. Spencer, West Newton, Mass., assigner toRay'theon Manufacturing' Company, Newton, Mass., a lcorporation of- Delaware ApplicationfMarch 27, 1945, Seria/l No. '585,025

(Cl. S- 40) 12 Claims.

My present-invention relates to electron-discharge devices, andmore particularly to electrondischarge devices -of ,the so-called magnetron type, which: are 'adapted' to generate electrical oscillationsv having a wavev length 4of the order of aiew centimeters,or less.v

One of the -objectsof .my present invention is to provide an anode structure for a magnetron, which is of such design astoenable building said magnetron Aof lsufficient Asize to generate appreciable power and, 'at the `same time, maintain the -wavelength oi the output thereof within the limits above .referred to.

Another object -of my present invention is to enable `the lattainment of the foregoingl object in' a simpler manner than has heretofore lbeen possi-ble.

These vand other- -objects vof my Apresent invention, which will become more apparent as the detailed` description thereof progresses, are attained, briefly, theriollowing manner:

I so construct the electron-discharge device of my present invention as to include an anode structure, preferably, the form of a cylindrical body provided with -a plurality of interiorlyextending, radiallil-'disposedI anode members. Said anode members are of such size that each alternate pair thereof, together with that por tionoi said cylindrical body lyingv therebetween, constitute a resonant :line at a frequency, for example, lower than that desired on the iinal output of thedevice.

I connect each intermediate pair of said anode members', at :points along their length, with Ia lowi-mped'ance memben-whereby the innerportions of adjacent anode members so connected, together with saidlow--impedancememberflikewise consti-- tute a resonant line, butY at al frequency, for example, higher than that desired of said nal output.

Itwill beobserved that .aportion of each of the connected .anode members is common to two difterently-dimensioned resonant lines, and this is preferred construction.

I 1li-ave found that by building the device as above, the output thereof includes appreciable power of a wave length which A is the average of the wave lengthsfof `the two dii'erently-dimensioned resonant llines formed in `the-anode structu-re.

In the accompanying specification I shall describe, and inthe annexed drawings show, an illustrative embodiment of the `electron discharge device of my present invention.

Inl the drawings,

Fig. 1 is a longitudinal sectional" view taken substantially through thel vcenter of an electron- -discharge device made in accordance with my present invention; andv Fig. 12 is a transverse vse'cti'onal'view taken along line '2-'2 o'f-Fig. 1.

Referring now more in detail to the aforesaid illustrative embodiment "ofl mytpresent invention, and with particular reference 'to the drawings illustrating 'the same, the numeralv 5 generally designates an electron-discharge ldevice yof v'the magnetron type. Such 'a device includes' 'an anode .structure 6, a cathodefstructure 1, and magnetic means B for `establishing a magnetic i-lel'd lin a direction 'perpendicular to "thepath -of the electron-owbetween said cathode vanclfanode structures.

The anodek structure` 6 comprises, preferably, a hollow cylindrical bodyl 9', made of h'iglyy conductive' material, such las copper, and having its interior provided Vwith an vannular bossifufrom which' vextends a' plurality, here shown as sixteen, ofV interiorly-extending radially-disposed -anode members inthe form of vanes H Each alternate pair of adjacent anodeinembers; 'together with that portion of the boss I'U of thecylindricalbody `9-`-lying therebetween, :con- 'stitute a resonant line, for example, at 'a-freq'uency which is lower than that desired ofthe final output of the device.

The adjacent anode'members l'lof 'each intermediate pair thereof lare connected, at points located along theirlength, saidl Alocations'depending uponthe frequencyb desired of the 'second' of 'the above rei-erred -to resonant lines, by a lowimpedance member l2', for example, fa conductm'g strap, whereby eachy such `coiint-icted pai-r of'anode members, together with the low-impedance member therebetween, constitute, respectively, 'each of 'saidfsecond' resonant lines; The dimensions Iof said 'second' resonant lines may besuch that each is resonant at a frequency which is'liigher than that desired' of the final'ontput of the device.

While not limited thereto, it 'is preferred, in the interest of simpler manufacturing technique, that each of the anode members Iil befprbvided, in their -u-pper and lower edges, 'with slots I3,

initially,Y conducting' rings may [be secured. Subsequently, 'those portions of. such rings as connect the adacent anode' members TH of 'alternate pairs thereof canbe removed, vleav ing the straps l2, and thereby forini'ng'thel two dinerently-dimensioned resonant lines above de'- scri'bed. y

The yanode Structurae' is closed at itsends, for

example, by end plates I4 and l5, the junctions between the cylindrical body 9 and said plates ld and I5 being hermetically sealed, as at IS.

The cathode structure 1, which is coaxial with the anode structure 6, may include a highly electron-emissive, oxide-coated sleeve l1, adapted to be heated by a lament (not shown) having terminals i8 and I9 electrically connected to lead-in conductors and 2|, the latter being, in turn, connected to an appropriate, external source of E. M. F. (not shown). Said lead-in conductors may enter the device through glass seals 22 and 23, fused into pipes 24 and 25, threadedly engaged and hermetically sealed in the cylindrical body 9.

Mounted in any preferred manner, immediately adjacent the end plates I4 and l5, is a pair of pole pieces 2E and 21, said pole pieces being disposed, as previously indicated, to establish a magnetic field in a direction perpendicular to the path of the electron-flow between the cathode structure l and anode structure 6.

In order to extract power from the device, I may, for example, introduce a loop 28 into the space between any two of the anode members Il forming the longer of the aforementioned resonant lines, said loop being connected to a conductor 29, embedded in a glass seal 30 fused into the outer end of a pipe 3i, in turn, threadedly engaged and hermetically sealed in the cylindrical body 9 of the anode structure.

Now, by suitably heating the cathode of the device, and applying a proper potential difference between said cathode and the anode, the device will generate electrical oscillations of frequencies determined, primarily, by the distributed capacitances and inductances built into the same as a function of the geometry thereof, more especially, of the dimensions of the elements making up the aforementioned resonant lines.

It will be found that, while the device oscillates at wave lengths corresponding to the two differently-dimensioned resonant lines incorporated therein, there will be present, in the output thereof, appreciable power of a wave length corresponding to the average of the wave lengths of said differently-dimensioned lines, and the latter may be extracted, for example, by an appropriately tuned circuit 32.

This completes the description of the aforesaid illustrative embodiment of my present invention. It will be noted from all of the foregoing that I have provided an electron-discharge device of the magnetron type, which includes an anode structure so designed that, although the output of the device is of very short wave length, the device as a whole may be of substantial size, thus permitting the generation of appreciable power. It will also be noted that the design of the device is simple, and is such as to enable its relatively easy manufacture.

Other advantages of my present invention will readily occur to those skilled in the art to which the same relates.

W'hat is claimed is:

1. An electron-discharge device comprising: an anode structure provided with a plurality of anode members; at least one pair of said anode members, together with at least a portion of the anode structure lying therebetween, being electrically effective to constitute a rst, shorted transmission line of predetermined dimensions adapted to resonate at a first, predetermined wave length; a low-impedance member connecting at least one pair of said anode members at points intermediate the length thereof; a portion of each of said connected anode members, together with said lowimpedance member, being electrically effective to constitute a second, shorted transmission line of different dimensions than said first-named transmission line and adapted to resonate at a second, predetermined wave length; and an output circuit, tuned to the average of the resonant wave lengths of said first and second transmission lines, coupled to at least one of said transmission lines.

2. An electron-discharge device comprising: an anode structure provided with a plurality of anode members; at least one pair of said anode members, together with at least a portion of the anode structure lying therebetween, being electrically effective to constitute a first, shorted transmission line of predetermined dimensions adapted to resonate at a first, predetermined wave length; a conductive strap connecting at least one pair of said anode members at points intermediate the length thereof; a portion of each of said connected anode members, together with said strap, being electrically effective to constitute a second, shorted transmission line of different dimensions than said first-named transmission line and adapted to resonate at a second, predetermined Wave length; and an output circuit, tuned to the average of the resonant wave lengths of said first and second transmission lines, coupled to at least one of said transmission lines.

3. An electron-discharge device comprising: an anode structure provided with a plurality of interiorly-extending, radially-disposed anode members; at least one pair of adjacent anode inembers, together with at least a portion of the anode structure lying therebetween, being electrically effective to constitute a first, shorted transmission line of predetermined dimensions adapted to resonate at a first, predetermined wave length; and a low-impedance member connecting at least one pair of adjacent anode members at points intermediate the length thereof; a portion of each of said connected anode members, together with said low-impedance member, being electrically effective to constitute a second, shorted transmission line of different dimensions than said first-named transmission line and adapted to resonate at a second, predetermined wave length.

4. An electron-discharge device comprising: an anode structure provided with a plurality of interiorly-extending, radially-disposed anode members; at least one pair of adjacent anode m'ernbers, together with at least a portion of the anode structure lying therebetween, being electrically effective to constitute a first, shorted transmission line of predetermined rdimensions adapted to resonate at a rst, predetermined wave length; and a conductive strap connecting at least one pair of adjacent anode members at points intermediate the length thereof; a portion of each of said connected anode members, together with said strap, being electrically effective to constitute a second, shorted transmission line of different dimensions than said first-named transmission line and adapted to resonate at asecond, predetermined wave length.

5. An electron-discharge device comprising: an anode structure provided with a plurality of anode members; at least one pair of said anode members, together with at least a portion of the anode structure lying therebetween, being electrically effective to constitute a first, shorted transmission line of predetermined dimensions adapted to resonate at a first, predetermined wavelength; a low-impedance member connecting atleast one pair of said anode members at points intermediate the length thereof, whereby a portion of each of said anode members so connected is common to said rlrst transmission line and to a second, shorted transmission line of different dimensions; said portions of each of said connected anode members, together with said low-impedance member, being electrically efectiva to constitute said second, shorted transmission line, which is adapted to resonate at a second, predetermined wave length; and an output circuit, tuned to the average of the resonant wave lengths oi'said iirst and second transmission lines, coupled to at least one of said transmission lines.

6. An electron-discharge device comprising: an anode structure provided with a plurality of anode members; at least one pair of said anode members, together with at least a portion of the anode Structure lying therebetween, being electrically effective t0 constitute a rst, shorted transmission 1in@ 0f pledetermined dimensions adapted to resonate ai; i. rst, predetermined wave length; a, conductive strap connecting at least one pair of said angle members at points intermediate the length thereof, whereby a portion of each of said alude members so connected is common 1-,0 said frst transmission line and to a second, shorted/transmission line of different dimensions; Said pyitions of each of said connected anode members, together with said strap, being electricajly eiective to constitute said second, shorted transmission line, which is adapted to resonate ai; ,i second, predetermined Wave length; and an Oyput circuit, tuned to the average of the resolrant wave lengths of said rst and second transmission lines, coupled to at least one of said y, transmission lines.

7. An electron-discharge device comprising:

an anode structure provided with a plurality of interiorly-extending, radially-disposed anode members; each alternate pair of adjacent anode members, together with that portion of said anode structure lying therebetween, being electrically effective to constitute a first, shorted transmission line of predetermined dimensions adapted to resonate at a rst, predetermined Wave length; and a low-impedance member connecting each intermediate pair of adjacent anode members at points intermediate the length thereof, whereby a portion of each of said anode members so connected is common to one of said rst transmission lines and to a second, shorted transmission line of different dimensions; said portions of each of said connected anode members, together with said low-impedance member, being electrically effective to constitute said second, shorted transmission line, which is adapted to resonate at a second, predetermined wave length.

8. An electron-discharge device comprising: an anode structure provided with a plurality of interiorly-extending, radially-disposed anode members; each alternate pair of adjacent anode members, together with that portion of said anode structure lying therebetween, being electrically effective to constitute a rst, shorted transmission line of predetermined dimensions adapted to resonate at a rst, predetermined wave length; and an arcuate conductive strap connecting each intermediate pair of adjacent anode members at points intermediate the length thereof, whereby a portion of each of said anode members so connected is common to one of said rst transmis` sion lines and to a second, shorted transmission line of different dimensions; said portions of each of said connected anode members, together with 6 said strap being electrically effective to constitute said second, shorted transmission line, which-is adapted to resonate at a second, predetermined wave length.

9. An electron-discharge device comprising: an anode structure provided with a plurality of interiorly-extending, radially-disposed anode members; each alternate pair of adjacent anode members, together with at least a portion of the anode structure lying therebetween, being electrically effective to constitute a irst, shorted transmission line of predetermined dimensions adapted to resonate at a rst, predetermined Wave length; a low-impedance member connecting each intermediate pair of adjacent anode members at points intermediate the length thereof a portion of each of said connected anode members, together with said low-impedance member, being electrically eiective to constitute a second, shorted transmission line of different dimensions than said first-named transmission line and adapted to resonate at a second, predetermined wave length; and an output circuit, tuned to the average of the resonant Wave lengths of said rst and second transmission lines, coupled to at least one of said transmission lines.

10. An electron-discharge device comprising: an anode structure provided with a plurality of interiorly-extending, radially disposed anode members; each alternate pair of adjacent anode members, together with that portion of said anode structure lying therebetween, being electrically effective to constitute a rst, shorted transmission line of predetermined dimensions adapted to resonate at a rst, predetermined wave length; a low-impedance member connecting each intermediate pair of adjacent anode members at points intermediate the length thereof, whereby a portion of each of said anode members so connected is common to one of said rst transmission lines and to a second, shorted transmission line of diierent dimensions; said portions of each of said connected anode members, together with said low-impedance member, being electrically eiective to constitute a second, shorted transmission line of different dimensions than said firstnamed transmission line and adapted to resonate at a second, predetermined wave length; and an output circuit, tuned to the average of the resonant wavelengths of said rst and second transmission lines, coupled to at least one of said transmission lines.

11. An electron-discharge device comprising: an anode structure provided with at least three adjacent anode members; one of the outer and the intermediate of said anode members, together with that portion of said anode structure lying therebetween, being electrically effective to constitute a rst, shorted transmission line of predetermined dimensions adapted to resonate at a first, predetermined Wave length; and a low-impedance member connecting the remaining outer and said intermediate anode members at points intermediate the length thereof; a portion of said connected anode members, together with said 10W-impedance member, being electrically eiective to constitute a second, shorted transmission line of different dimensions than said rst-named transmission line and adapted to resonate at a second, predetermined wave length.

l2. An electron-discharge device comprising: an anode structure provided with at least three adjacent anode members; one of the outer and the intermediate of said anode members, together with that portion of said anode structure lying V1--mrebetmeenbeingy eleetrc'aflly effective,- to monxstituteaa ,'rst, fshonted; tr-ansnsson lineofgprede- :stermnedzd-imensions adapted to fresonate., .at a rst, predetermined wave length; and afconduc- 'finalisti-ap; connecting ,the remaining'` outer fand V1,-rsa'd interme'date,fanode members at points nter- `v .:ruecliaate;theength thereof ;A a; portion of: said-:conffnectedranodefmembers, `'tog-ether with -sadstrap, "Hbeiuglectrcallyaetfectve to constitute a,- second, eshortedztransmissonline of different dimensions y"-fthani-sad rstenamed transmission line ,and

r-daptedntoa'resonateat a second; predetermined wavelength A ,BERCY L.-sPENcER.

. v- REFERENCES *CIT-ED "'Theifol-lofw-ing referentes vare of Zrecord inl'V the me of Ethsepa'ttent:

18 @U'NIIEDfS'IT-A'IPES PA'I'ENTS 'lName Date "Fritz Mar. 15, 1938 Dellenbach July 25, 1939 --'Blewett etal June 24, 1941 "Berline July 29, 1941 Blggs et al Oct. 8, 1946 'Hartman Jan. 14, 1947 I-Iagstnmtn. Apr. 8, 1947 Bondley June 17, 1947 'Okress Oct. 21, 1947 'Bondley e July 6, 1948 f FOREIGN PATENTS Country"\f Date '.Great113ritain` June4 1'7. 1940 RE I, 

